1. Field of the Invention
The present invention relates to an ophthalmic photographic apparatus, and more particularly to an ophthalmic photographic apparatus such as a fundus camera or the like that can be used for non-mydriatic and mydriatic color photography, for photography by visible light-excited fluorescence and for photography by infrared light-excited fluorescence.
2. Description of the Prior Art
There are ophthalmic photographic apparatuses such as fundus cameras and the like that in addition to being capable of photographing non-mydriatic or mydriatic color images of the eye fundus, are also capable of photographing eye fundus images by visible light-excited fluorescence (also designated as fluorescein angiography; FAG) or by infrared light-excited fluorescence (also designated as indocyanine green angiography; ICG). For each such photographic mode, a camera is provided having characteristics suitable for observation and for obtaining dynamic and still images. In each mode, cameras are switched, the photographic light source is controlled, and the recording method is switched.
For example, Japanese Patent Laid Open Publication No. 211120/90 discloses a fundus camera in which in the initial stage of fluorescence photography, a TV camera is used for dynamic image photography, and in the intermediate stage a still camera is used to obtain still images; Japanese Patent Laid Open Publication No. 189341/92 discloses a fundus camera in which the photographic light source is not allowed to flash when the system is switched to photography by infrared light-excited fluorescence; Japanese Patent Laid Open Publication No. 35639/92 discloses a fundus camera that records field images of the eye fundus during fluorescence photography and frame images of the fundus during normal photography; Japanese Patent Laid Open Publication No. 322802/96 discloses a system in which the images acquired depend on the type of recording system used; and Japanese Patent Laid Open Publication No. 224730/90 discloses a system in which the camera gain is changed for observation and photography.
However, a problem with using a fundus camera for the various photographic modes such as mydriatic photography, non-mydriatic photography, photography by visible light-excited fluorescence and photography by infrared light-excited fluorescence is that a separate camera is required for observation during non-mydriatic photography, for observation and photography of dynamic images during infrared light-excited fluorescence, and for photography of still images by infrared light-excited fluorescence. Another problem is that it is difficult to simultaneously acquire dynamic and still infrared light-excited fluorescence images, while a further problem is that each setting has to be changed each time there is a change in photographic modes.
It is therefore an object of the present invention to provide an ophthalmic photographic apparatus that with a simple operation is able to capture dynamic and still images by infrared light-excited fluorescence.